With the abuse I was subjecting the drives to, I found over time, I was breaking the steel cable portion of the chains. The engineers at Hobie determined it was only a problem when logging miles in the 4 digit range, but made a very subtle modification using a more rounded piece that the cable bends around before attaching to the drive. It eliminates a slight twist when the pedals are fully extended. It has proven to be a good fix since there was no observable wear that I could detect. It's gone back to the factory for closer inspection, but I see no need to carry extra chains on the long hauls. Everything else seems the same so there's no difference in performance."